It is known that communication networks allow to provide users with a number of data services (for instance, Internet access, e-mail, exchange of messages, video-on-demand) and/or telephone services (for instance, calls and conference calls).
A user may access such services by means of a terminal, which can be either a fixed terminal (i.e. a terminal which is connected to the communication network distributing the services through a wired connection) or a mobile terminal (i.e. a terminal which is connected to the communication network distributing the services through a wireless connection). Exemplary mobile terminals are the GSM (Global System for Mobile communications) or UMTS (Universal Mobile Telecommunication System) mobiles and the laptop computers provided with a GSM or UMTS interface, or with a Bluetooth or Wi-Fi interface.
A terminal (in particular, a mobile terminal) is frequently equipped with a number of sensors allowing to detect context information about the terminal. In the following description and in the claims, the expression “context information about a terminal” will designate a set of information indicative of the context (i.e. the environment and/or the operating status) in which the terminal is put. Exemplary context information are:                the terrestrial coordinates at which the terminal is located, which may be detected by the mobile network (on the basis of measurements done by the terminal or by the network) or which may be detected by a GPS device installed on the terminal, and which allow to determine the location of the terminal;        the identifier of the mobile cell in which the terminal is located, which may be detected by any GSM or UMTS mobile, and which is indicative of the location of the terminal;        the luminosity and/or the temperature and/or the humidity of the environment surrounding the terminal, which can be detected by suitable sensors installed on the terminal, and which are indicative of the environment surrounding the terminal (i.e. whether it is an outdoor environment or an indoor environment, etc.);        the acceleration to which the terminal is subjected, which can be detected by an accelerometer installed on the terminal and which is indicative of whether the user is moving or standing; and        the presence of other terminals in the environment surrounding the terminal, which can be detected e.g. by a Bluetooth interface or a Wi-Fi interface (in order to be detected, also the other terminals should be equipped with a corresponding interface).        
Recently, service providers are able to collect context information from the terminals of their users, and to process them for providing data services and telephone services which are capable of adapting themselves to the context of the terminals. In the following description and in the claims, the expression “context-based service” will designate a data service or a telephone service which is capable of acquiring context information from a terminal and to use such context information for adapting itself to the context of the terminal.
WO 2006/097778 discloses a method for sending environmental data by means of a mobile terminal device, comprising the steps of detecting said environmental data, evaluating said environmental data, determining if said evaluated environmental data is to be sent, and sending said environmental data in case of an affirmative determination. In particular, each mobile terminal device is equipped with a wireless data interface for sending and receiving data packets to and from a service provider. Said service provider is equipped with a data storing module for storing the received data, originating from said plurality of mobile terminal devices. Additionally, each mobile terminal device has a sensor for detecting and preferably recording environmental data. These environmental data may comprise humidity, luminance, temperature, position and the like. Said mobile terminal device records the environmental data and it is adapted to evaluate it. The devices are enabled to decide either the data shall be temporarily stored or sent to said service provider.
US 2007/006098 describes methods that utilize a geographic location technology (e.g., GPS) to determine user location data, and existing network-based websites (e.g., Internet websites) for searching and accessing data related to the location data such that the user context can be developed and stored.
WO 2002/093877 discloses a context sensitive web services method that enables a mobile phone or wireless device to use context inference techniques to sense the user's environment and in response, to provide useful information to the user that is appropriate to the user's perceived environment. The method includes the steps of receiving sensor signals characterizing a current environment of the wireless device; processing the sensor signals with a context inference engine; outputting a current context result from the processing by the context inference engine; and providing useful information to the user in response to the current context result.
WO 2004/089006 discloses a mobile station for managing context-related information including at least one sensor capable of measuring at least a portion of at least one condition of the mobile station. The mobile station also includes a context engine capable of storing context-related information based upon the portion of the condition(s), where the context engine is also capable of managing an exchange of the context-related information with at least one context consumer. The mobile station further includes a privacy engine, a script engine and a communication manager. The privacy engine can provide security and/or privacy to the exchange of the context-related information. The script engine can execute at least one context rule relating to at least a portion of the context-related information. And the communication manager can communicate with at least one context consumer external to the mobile station for the exchange of context-related information
WO 2006/106303 discloses a system for processing context data comprising means for receiving context data from a plurality of sources; means for producing context information from the received context data according to a predetermined rule-set including a plurality of rules; and means for communicating the context information to at least one application, wherein the system includes means for permitting at least one protocol-source to specify instructions and/or rules related to a communication protocol for communication between the protocol-source and the system, thereby updating the means for receiving and/or the means for communicating.
US 2006/184616 discloses a method of managing conflicts between context-aware applications by use of semantics of abstract service for group context information management. The method includes detecting and resolving a conflict between context-aware applications; upon receiving a service request from an application, analysing a semantic of the requested service; and registering the semantic into a data structure.
US 2006/074633 discloses a method for improved diagnostic reading and workflow in a healthcare environment using rules-based context management. In an embodiment, the system includes a plurality of information sources, wherein each of the plurality of information sources includes information. The system also includes a rules engine including at least one rule governing at least one of availability and presentation of information.
CA 2431491 discloses an architecture having a centralized storage location coupled to a context manager for servicing and logging context events from a plurality of sources. This type of system uses a synchronization scheme to perform orderly storage and retrieval of data to and from the centralized storage location.
The paper “A Context Query Language for Pervasive Computing Environments” from Roland Reichle et al., Proceedings on 5th IEEE Workshop on Context Modeling and Reasoning (CoMoRea) and 6th IEEE International Conference on Pervasive Computing and Communication (PerCom '08), Hong Kong, 17-21 Mar. 2008, discloses requirements for querying and accessing context information in mobile and pervasive computing environments. Furthermore it studies existing query languages and it is shows that they satisfy only a subset of these requirements or cover some of them only to a limited extend. Therefore, it presents a context query language to overcome these shortcomings. It explicitly addresses heterogeneous representations of context information, definition of complex filtering mechanisms, elaborate aggregation functions and ontology integration, all in one language.